Temperature sensor blinks, but the needle doesn't move

[mazzidumato]

Hi all.

Been having some electric issues with the van. The other day I was driving and all of a sudden I saw smoke in my rearview mirror. The electric wire from the battery caught fire. Luckily I was able to put it out before any serious damage. Now I retaped it while im getting a new cable replaced.

But on the other hand, the temperature sensor lever stopped going up and down after a few days from the above incident. I don't think it's related but since the lever doesnt move but the light blinks, im wondering if I loosened a wire by mistake. Where would I find the wire for the temperature indicator?

thank you.

[Ahwahnee]

Better say what year you have - on my 84 the temp gauge sender is on the thermostat housing.

Another place things can get loose is the foil circuits behind the dash pod. Some of those depend on little nuts being tight to make good connections... the blinky is one, cannot recall if the gauge is another.

[SyncroHead]

The blinking light for the coolant LEVEL can operate properly while the gauge for TEMPERATURE may fail. The "needle" (you wrote "lever", usually called "needle") for the temperature is very sensitive to proper voltage and uses a voltage regulator "chip" on the back side of the instrument cluster. This voltage regulator can be damaged by over-voltage, for instance if the voltage regulator in the alternator fails. I would suspect you may have had a voltage spike during the fire and that this fried the instrument voltage chip.

Here's what that part is:
https://www.gowesty.com/product/gauges-instrument-...luster-?v=

Regards,
Jim Davis
_________________
"A Vanagon? It's not a car or a van. It's a hobby!"

Check out:
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www.SyncroSafari.org and
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[mazzidumato]

I took the van to the mechanic and the cables from the main battery was fried.

The cables were replaced but there is one cable that the mechanic overlooked and im wondering what this is for.


In the image below I highlighted in red the cable that hasnt been replaced. Any information on what is this for and maybe the reason the van sometimes still dies while driving

[dobryan]

Was that cable fried or just left unplugged?

If just left unplugged it should be plugged in. If fried you'll need to get a replacement. The samba classifieds may have one.

Yes it is needed.
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

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https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

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[mazzidumato]

yes it is partly melted. But what is it for?

And Im wondering if it has to do with the car sometimes stalling while driving.

[Wildthings]

It is not a cable, but a bundle of wires. The wires are how the AFM (air flow meter) communicates with the ECU (electronic control unit). The bundle runs through a sheath, the sheath could look pretty bad and the wires inside of it could be just fine. A close inspection of the damaged area would tell you what you need to do to fix it, though most likely you would either need to do nothing or just to apply electrical tape over the damaged area.

If the wires inside the sheath were very badly damaged, you engine probably would not run or would run very poorly. A close visual inspection of the damaged area needs to be done.

I am guessing that the wiring that went bad is what is known as the alternator harness. You can buy an upgraded alternator harness from Go Westy or Vancafe for very little. While it is possible to build this harness from scratch, the design of the original was poor and any copy of the original would also be poor. As you have seen this was not one of VW better bits of engineering.

As mentioned, you blinking light could be a problem with the coolant level sensor which resides in what VW calls the Expansion Tank, you can see part of the tank in the lower left of your picture. Your tank is old and brown and likely on the verge of failing, the level sensor also get old and will fail. Replacing the two as is unit is usually the best thing to do. Note that two different sensor were used over the years and you need to get the correct one that matches your original. The blinking light can also come on because of issues with your wiring or even issues with the electronics in the dash.

The coolant temperature sender resides in the lower part of the thermostat housing to the front left of your engine. There are two senders in the housing, one for the gauge and one for the fuel injection, they are not interchangeable yet it is possible to install the plugs on the wrong sender, the senders and their plugs are color coded to match. Again the wiring could be the issue and not the sender.

You need to supply specifics about your vehicle when asking questions if you want worthwhile answers. Year, engine code and size, fuel injection type, transmission type, etc.

[candyman]

Off topic, very clean engine! I want to point out that it appears to be original fuel lines, esp the ones coming from the firewall. In addition looks like some original red braided cloth coolant hoses as well. While your chasing your temp needle issue, I would certainly address the fuel lines and coolant hoses as well. Hate to another syncro lost to a car-b-que. coolant hoses could wait but you may consider adding that to the list. Again, very clean engine!